What does backslash mean?
A backslash is the typographical symbol \, a stroke that slants from upper left to lower right — the mirror image of the ordinary slash (/). Though rare in everyday prose, it is indispensable in computing: operating systems such as Microsoft Windows use it to separate directories in file paths, and programming languages employ it as an escape character, marking the next symbol as having a special or literal meaning. It also appears in regular expressions, markup languages, and command-line syntax. Because the two slanted strokes look similar at small sizes, writers frequently confuse the backslash with the forward slash, so precision matters when typing paths, URLs, or code; a misplaced backslash will usually break them. The word itself combines 'back' with 'slash', reflecting the direction of the mark. For anyone working with computers even casually, knowing which way each slash leans is a small but genuinely practical piece of literacy.
nounA backslash is the typographical symbol \, a reverse solidus that slants from upper left to lower right. It is used chiefly in computing, where it serves as an escape character and as a path separator in file systems such as those of Windows.
- The typographic symbol \ used in computing as an escape character and as a directory separator in Windows file paths.
"Type the full file path, making sure to separate each folder with a backslash."
"In Windows, folders in a path are separated by a backslash, as in C:\Users\Documents."
"In many programming languages, a backslash before a character signals that it should be treated literally rather than as code."
Standard plural; note the spelling change of y-less final 'sh' plus '-es'.
"Windows paths are full of backslashes, while web addresses use forward slashes."
The backslash didn't exist as a standard character until computing needed one — it was essentially invented so programmers could tell a slash which way to lean.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of backslash
The word backslash is a straightforward English compound of 'back' and 'slash', coined in the computing era to name the newly prominent reverse-leaning counterpart of the slash. The slash itself descends from the Latin solidus, the Roman coin whose name was later borrowed by printers and mathematicians for the diagonal division mark. The backslash character gained currency with the rise of computing in the second half of the twentieth century, when systems needed a distinct escape character and Microsoft adopted it as a path separator.
How backslash is actually used
Backslash is primarily a technical term; outside computing it appears mainly when describing keyboard characters or distinguishing the symbol from the forward slash. It carries no emotional connotation and is neutral in register.
Easily confused with backslash
A slash (/) leans forward (lower left to upper right) and commonly means 'or' or separates dates and fractions, while a backslash (\) leans the opposite way and belongs mainly to computing contexts.